Window and blind arrangement



Jan. 13, 1942.

A. H. CHILTON WINDOW vAND BLIND ARRANGEMENT Filed May 24, 1938 4Sheets-Sheet l Jan. 13 1942.

, A. H. CHILTON 2,269,579

WINDOW AND BLIND ARRANGEMENT I Filed May l24, 1938 4 Sheets-Sheetl 2 4Sheets-Sheet 3 `A. H. CHILTON wINDow AND BLIND AHRANGEMENT Filed May 24,1958 Jan. 13, 1942.

Jan. 13,1942. A, H CmLTON 2,269,579

wINDow AND BLIND ARRANGEMENT l Filed May 24, 1938 4 sheds-sheet 4,aren/aff',

www VW Patented Jan. 13, 1942 2,269,579 WINDOW AND BLIND ARRANGEMENTAlfred Henry Chilton, London, England, assignor,

by mesne assignments, to The Safety Car Heating & Lighting Company,Inc., New York, N. Y., a corporation of Delaware Application May 24,193s, serial No. 209,825 In Great Britain May 28, 1937 18 Claims. (Cl.189-64) This invention concerns improvementsV relating to windows andwindow blinds, screens or shutters (hereinafter termed blinds) andhas'for its principal object to provide an effective arrangement for usein cases where it is desired to limit the penetration through the windowof thermal radiation.

An example of a case where the effective solution of this problem is ofespecial importance is that of railway coaches provided with air-coolingequipment for use in hot climates. tical reasons, there are limits tothe capacity of the cooling equipment and it is therefore essential thatthe leakage of heat into the coach should be reduced to a minimum.Thermal insulation of the body of the coach leaves the windows asvulnerable points by which considerable heat can enter.

The use of double windows cuts down the entry cf heat to some extent andbetter results can be obtained by the use of external shutters inconjunction with such double windows. In practice, however, there arevarious objections to the latter arrangement, particularly on railwaycoaches. For example, it would be dilricult to make satisfactoryprovision for adjustment 'of the shutters. Also it would be difficult tokeep the window-arrangement clean and in good order.

The last-named objection applies also to arrangements, as proposedheretofore, in which a blind is provided between the panes of a doublewindow. Particularly in the case of railway coaches which are exposedfor unlimited periods not only to every kind of adverse weatherconditionbut also to constant steam, smoke and dirt, the proposed arrangementswould allow moisture and dust to enter the space between the panes,obscuring the latter and fouling the means for operating the blind.

With the object of overcoming these dificulties, the arrangementaccording to the invention comprises a double window with the space-between the panes hermetically sealed and a blind adapted for beinglowered or extended in the said space by means operated from outside thesaid space. Preferably, the panes are hermetically sealed around theentire peripheries thereof by sealing means held tight by removablemechanical means. With this arrangement, not only can the penetration ofthermal radiation be reduced to a minimum and satisfactory provisionmade for adjusting the blind in the space between the panes, but alsothe said blindand the adjusting means will be completely protected, sothat they will remain unalfected by the influences f the Forpracweather, steam and so forth for indefinite pe riods.

In a preferred form of the invention, the blind together to leave thewindow substantially'unobstructed.

Advantageously the slats are iixedly connected to respective links oflazy tongs whereby the said blind is operated. With this arrangement, aswill be understood, the slats are positively set in the inclinedoverlapping relationship, as. well aslowered or extended, by the" lazytongs. Furthermore, the slats are collectedV together by even closing upthroughout the length of the blind and not progressively from one end.Consequently, the window is not inconveniently obstructed inintermediate positions of the blind.

The blind may be operated through the intermediary of endless cablevmeans so devised that the blind is both opened and closed by a positivedriving action. Reliance upon gravity or springaction can then beavoided. The Vblind may be operated by the power of an electric motorAenclosed in the sealed space between the panes of the window or enclosedin a sealed casing connected to the said space.

Examples of applications of the invention to the windows of railwaycoaches will now be described with reference to the accompanyingdrawings, in which:

Fig. l is a general inside elevation of a preferred window and blindarrangement,

Fig. 2 is a `diagrammatic view showing the cable disposition in the saidarrangement, y

Fig. 3 a composite view to a larger scale,.the lower half being a sideelevation with part of the frame broken away to show the lazy tongs andthe upper half a vertical section at the middle of the window,

Fig. 4 an inside elevation of one side of the window, also to a largerscale and with `parts cf the frame broken away,

Fig. 5 a section on the line V-V in Fig. 4, 1

Fig. 6 a vertical section showing the mounting and driving 'arrangementfor the motor,

Fig. 'l an inside elevation (with parts of the frame broken away) of asecond arrangement,`

Fig. 8 a section on the line VIII-VIII in Fgf,

Figs. 9 and 10 are views similar to Figs. 7 and 8 of a thirdarrangement, and

Fig. 11 is a diagrammatic elevation showing a modification.

In all of the arrangements illustrated, the blind is of the nature of aVenetian blind, but has the individual slats I carried by lazy tongs 2located at the sides of the window. The slats are conveniently of metal,for example aluminium or a light alloy, or of wood or artificial resinwith a cellulose finish and are mounted upon corresponding inner linksof the lazy tongs. In the arrangement illustrated in Figs. 1-6, in whichthe lazy-tongs are to be concealed from view by a housing 3, the ends ofthe slats are forced tightly into slots in the inner faces ofSlat-holders 4 which extend substantially parallel to the inner linksand are connected centrally thereto by necks 5 passing through avertical slot 6 in the housing 3. As in the arrangements of Figs. 7-10,the slats may lalternatively be forced into slots between cheeks 'I onthe faces of the inner links themselves or into slots cut in the saidlinks. These modes of mounting the slats are not only simple andinexpensive, but permit of easy a.,- sembly of the said slats with thelazy tongs.

As shown in Figs. 1-6, the slats I are preferably provided withoppositely directed narrow flanges 8 at their longitudinal edges. Theseflanges not only stiffen the slats and assist in locating them in theparts 4 or 1, but also, by their overlapping in the lowered condition ofthe slats (Fig. 3), make it impossible to see through the blind. Formerely stiffening the slats, these may alternatively be beaded or rolledat the longitudinal edges or a slat having a shallow W-shaped or curvedcross-section may be employed.

The raised blind is to occupy a comparatively slight depth 9 (Fig. 3) atthe upper part of the window (say one tenth of the total depth) and isto be lowered to a condition in which the slats slope downwardly andoutwardly in slightly overlapping relationship at a small angle to thevertical, for example in Figs. 1-6 and 30 in Figs. 7-10. The fixed pivot|0 of each lazy tongs is secured to the respective side of thewindowframe nearly at the top thereof, but leaving a space for drivingmechanism to be described. For the sake of simple manufacture, thepivots between the links of the lazy tongs are preferably so-calleddrive screws.

In Figs. 1-6, the lowermost pivot of each lazy tongs is extended as alug I I in the forked end of which one fall I21 or I22 of an endlesscable I2 is secured. The course of this cable is illustrated in Fig. 2:Proceeding, say, to the left from the tensioning device I3, the cablepasses round a pulley I4 which is located parallel to the window and isfree on an axle I5 (Fig. 4) mounted in the window frame. The cable thenpasses down the side of the window, round a pulley I6 which is at rightangles to the window and is free on an axle I'I, and up to a secondpulley I4 free on the axle. I5. From this pulley, the cable passesacross the top of the window to the upper side of a pulley-groove I8 onone flange of a wheel-body I9 mounted on an axle 20. Thence the cablepasses round the under side of a similar groove I8 on the same flank ofa second wheel body 2|. The path of the cable on the right-hand sidethen duplicates that on the left hand side. The returning cable finallypasses over a groove I3 on the opposite flange of the wheel body 2| andunder a groove I8 on the opposite flank of the wheel body I9.

Iii)

The grooves I8 serve to drive the cable I2 for raising and lowering thelazy tongs 2. Between the said grooves, each of the wheel bodies I9, 2|is formed as a worm-wheel meshing with a worm 22 on a shaft 23 extendingvertically between the said wheels. The upper end of the shaft 23carries the rotor 24 of an electric motor 25.

The falls |21, |22 are selected so that, when the 'cable is driven inthe one or other direction, the lugs II will move up or down together,their movement being identical. The lazy tongs 2 are thereby movedpositively in both directions. Gravity and spring action are not reliedupon in any Way and the danger of jamming is minimised. The cable I2 maybe prestretched and made of such ample strength that stretching in thecourse of time need not be feared. The cable will not slip and the blindwill remain in the fully raised or a partially raised position evenunder con ditions of train vibration.

In Figs. 1-6, the frame of the window is made wholly of metal,preferably of extruded sections. The outer and inner panes 26 and 2'Iare embraced between flanged outer irame parts 28 (Figs. 3 and 5) andthe housing 3 which serves as a distance piece, a suitable spacing ofthe panes being 11A-1% inches. Rubber gaskets 29 and 3D separate theoutsides and the edges of the panes 26 and 21 from the frame parts 28. Achannel-shaped gasket 3| separates the insides of the panes 26 and 21from the housing 3. The gasket 3|, in particular, may be connected tothe panes by adhesive. When the above parts have been assembled, theyare laid between two face plates by which the frame parts 28 are pressedtogether and a drift 32 is slid over hook-like formations 33 on the saidparts 28 to lock the assembly together under a substantial compression.By this simple means, air tight joints are established all round theedges of the panes 2S, 2l without the use of screws. Moreover, thisconstruction of window is light and is simple to manufacture andassemble.

Where the shaft 23 penetrates the frame, it passes through a sleeve 34integral with a bracket 341 which is seated in the top of the housing 3and in which the axles are mounted. A boss 35 on the casing of the motoris mounted over the sleeve 34 and is clamped air-tightly against thegasket 3| by a nut 36 screwed on the sleeve. To enhance the tightness ofthe joint here, the end of the boss 35 may be recessed to t over acompressible packing ring. The motor 25 is itself totally enclosed, alljoints in its casing being carefully sealed, for example, by a bitumencompound. It will be seen that the blind and the mechanism, includingthe motor, are accommodated in a substantially hermetically enclosedspace and consequently they remain always unaffected by the Weather,clean and in good order. As moisture and dust cannot enter, internalsteaming, frosting and fouling are prevented. The window does notrequire to be taken apart for cleaning of the glass or slats. Theseproperties do not materially deteriorate with time and are unaffected bythermal expansion effects. Preferably the window, blind and mechanismare made up as a unit before being fitted to the coach, as air andweather tightness can thus be best assured. An advantage of theenclosure of the blind is that its operation is not impeded bv theeffects of wind or accidental obstruction; the blind may therefore belight and easy to operate,

The air which is sealed up in the double window may be dehydrated air.Alternatively or in addition, a small quantity of a dehydratingsubstance, such as silica gel, may be placed in the window before it issealed up.

When the slat blind is fully lowered, it is eifective, in combinationwith the double window, in intercepting a large proportion of thermalradiation incident upon the window. Some radiation is reflected orabsorbed by the outer pane 26. Of that which penetrates the pane 26, alarge proportion is reflected outwardly or absorbed by the slats I. Inany case no direct rays of the sun can pass the slats. Such heat as maybe passed by the slats has still to penetrate the inner pane 21. Thus avery small proportion of the incident heat enters the coach.Nevertheless, a suflicient amount of diiused light enters the coach,such light pass-ing the slats by repeated reflection. By raising theblind to an intermediate position, the slats are turned towards thehorizontal and an increased amount of light is admitted at the expenseof decreased heat insulation. The outer surfaces of the slats may behighly polished to enhance the outward reflection of the heat. Inpractice, however, it'may be preferred to make both surfaces matt. madethermally absorptive and nis-hed to suit the interior of the coach.

If required, at least one of the panes, preferably the outer, may bemade of thermally absorptive or tinted glass. panes may be internallyfrosted. By this means, the raised slats can be concealed without thenecessity for providing a special blind-storage housing.

The motor is advantageously a simple twophase squirrel-cage inductionmotor with which special starting switch-gear, limit switches and soforth are not essential. Such a motor can be designed so that, if itcontinues to be excited after complete raising or lowering of the blind,it simply stalls and, in this condition, carries its short-circuitcurrent harmlessly for a considerable period. The motors 25 of all thewindows of a coach may be controlled by a common pressbutton switchoperated by an oiiicial on the train. Alternatively the motors may beindividually controlled by press-button switches 37 which mayconveniently be mounted on or beside the motor 25 (Fig. 1) to shortenthe wiring necessary. The

supply of two-phase current for the motors may l be taken from a smallrotary converter.

In Figs. 7 and 8, each of the lugs Il is guided in a slot 3B in theframe .and is connected therein to one fall 3.91 or 392 of an endlesscable 39. This cable extends from a driving member 40 at the top of thewindow to a pulley 4|, down the side of the window, round a pulley 42,acrossthe bottom of the window, round one groove of a double-groovedpulley 43, up the other side of the window to one groove of adouble-grooved pulley 44, down the last-named side of the window, roundthe other groove of the pulley 43 and finally up the same side of thewindow and round the pulley 44 back to the driving member 40. Thepulleys are mounted on ball bearings in recesses 45 in the frame. Uponmovement of the driving member, the two lazy tongs 2 will be movedequally and in the same direction, as in the previous example. Thelength of the movement of the driving member 40 can be co-ordinated tothe required lazy-tongs movement in any particular case by appropriateselection of the lazy-tongs pivots to which the lugs Il are connected.

The driving member 40 comprises a nut travel- The inner surface may beOver the depth 9, the 0 All ling upon a screw-spindle 46 mounted inballbearings 4l carried at the sides of the frame. The nut has anextension 48 which passes through a slot 49 in a part of the frame andprevents the nut from turning on the spindle. Travel of the nut islimited by stops 50 at the ends of the slot. Above the slot, thisextension 48 is forked to embrace the cable 39 and engages, with someplay, between stops 5| fixed on the said cable. The spindle is driven byan electric motor 25 whose rotor is mounted directly on the spindle 46.

In this arrangement, the body-part 52 of the frame is made of hard woodand only the panesecuring parts 53 are made of metal. Both faces of theframe body'are recessed round their edges to receive the panes andsealing material for making a tight joint all round them.

In Figs. 9 and l0, the motor 25 drives the cable 39 directly through aworm 54 and worm-wheel 55 connected to the pulley 44. In this case, thelugs Il are connected to pivots at the ends of shortened lowermost links56 of the lazy tongs 2 and move in slots 38 to one side of the centreline of the said lazy tongs. This arrangement permits of the worm 54 andmotor 25 being disposed centrally at the end of the frame-part 51closing the top of the window. The off-centre disposition of the slots38 also results in the lazy tongs and the blind as a whole having aslight inclination to the frame of the window when the said blind islowered. This inclination assists in reducing the effect of vibrationupon the blind.

With this arrangement, if desired, the cable may be replaced by twocables, one passing round the pulleys at the four corners of the frameand the other passing round the pulleys at the righthand side of theframe only. The two cables are then adjustably coupled at a convenientpoint.

The links of the lazy tongs 2 in the arrangements described above may bemade of unequal lengths as illustrated in Fig. 11, the vslats l beingcarried on the longer links. In this case, the slats pack up at a largerangle when the blind is raised which is of advantage if it is desired touse comparatively wider slats l in relation to the space between thepanes 26, 21.

The above-described forms of mechanism, particularly thefirst-described, have many practical advantages: The operation of theblind is positive and silent. The mechanism comprises a few parts onlyand does not depend for its operation upon springs, automatic switchesand so forth. It is therefore reliable and will give a long life.However, other forms of mechanism may be employed: Separate endlesscables at the sides of the windowmay be driven from a motor at the topor bottom of the window through shafts extending from the motor to theadjacent pulleys and containing one or more flexible couplings. Orcablesmay be simply wound upon drums for raising the slats, gravity beingrelied upon to cause the slats to re-descend when required.Cable-transmission may even be dispensed with and lazy tongs may bedriven from a motor through bevel gearing and screw-spindles, The lazytongs may also be lever-operated: An example of this kind devised fordirect manual operation will be briefly described: Correspondinguppermost links of the lazy tongs are extended upwardly beyond thei'lxed pivots and are connected together at their upper ends by atransverse horizontal bar. A rod connected to the middle of the said barextends horizontally at right-angles thereto through a hole in an insidepart of the window frame. The projecting part of the rod is covered inair-tight manner by a metal bellows. The inner end of the rod is engagedthrough the flat end of the bellows by the end of a screw mounted in abracket on the frame and having a handle turnable from inside the coach.The arrangement is made such that, upon turning the screw in onedirection, the lazy-tongs are raised through the levers formed by theextended top links and, upon turning the screw in the other direction,the lazy tongs are lowered by the weight of the slats and other parts.

The blinds may also be actuated otherwise than electrically or manually,for instance pneumatically.

In the arrangements illustrated, the blind is substantiallyrattle-proof, it cannot be over-operated and its slats cannot interlockwith each other or the frame. However, other forms of Slat-blind may beemployed, for example a fixedangle Venetian blind or a blind composed ofchannel-shaped slats which are raised and lowered between an extendedand a nested condition by means of chains or cables.

Other forms of shutter or blind device may be used, for instance a blindwhich is rolled and unrolled. In this case and also with cabletransmission, use may be made of a long motor with an external rotorupon which the blind or the cable-means is rolled up.

As an alternative for manual switch control of the blinds, provision maybe made for automatic control by a thermostat exposed at 01 near theoutside of a window to the suns rays. The thermostat may be arranged toenergize motorcontrolling relays for a given period and after a certaintime-lag whenever the temperature rises above or falls below apredetermined value.

I claim:

1. In window construction, in combination, means forming a continuouslyperipheral frame, a pair of panes hermetically sealed in said frame inspaced relation to one another to form a space therebetween, a blindreciprocably disposed between said panes within said space and adaptedwhen lowered to cut oi thermal radiation through said panes whileadmitting a certain amount of light therethrough, and means including anoperating device wholly disposed within said space for reciprocatingsaid blind.

2. In window construction, in combination, means forming a continuouslyperipheral frame. a pair of panes hermetically sealed in said frame inspaced relation to one another to form a space therebetween, a blindreciprocably disposed between said panes within said space and adaptedwhen lowered to cut oi thermal radiation through said panes whileadmitting a certain amount of light therethrough, said blind comprisinga plurality of parallel slats adapted to nest together when the blind israised and adapted to lie in uniformly spaced relationship in anyposition of the blind, and means wholly disposed within said space forreciprocating said blind.

3. In window construction, in combination, means forming a continuouslyperipheral frame, a pair of panes herm-etically sealed in said frame inspaced relation to one another to form a space therebetween, a blindreciprocably disposed between said panes within said space and adaptedwhen lowered to cut oil" thermal radiation through said panes, saidblind comprising a plurality of parallel slats adapted to nest togetherwhen the blind is raised and adapted to lie in uniformly spacedrelationship in any position of the blind, and means wholly disposedwithin said space and connected to each of said slats to effectoperation thereof.

4. In window construction, in combination, means forming a continuouslyperipheral frame, a pair of panes hermetically sealed in said frame inspaced relation to one another to form a space therebetween, a blindreciprocably disposed between said panes within said space and adaptedwhen lowered to cut oi thermal radiation through said panes, said blindcomprising a plurality of parallel slats adapted to nest together whenthe blind is raised and adapted to lie in uniformly spaced relationshipin any position of the blind, and means including an endless cableconnected to said blind for raising and lowering said blind.

5. In window construction, in combination, means forming a continuouslyperipheral frame, a pair of panes hermetically sealed in said frame inspaced relation to one another to form a space therebetween, a blindreciprocably disposed be tween said panes within said space and adaptedwhen lowered to cut off thermal radiation through said panes, and lazytong means connected to said blind and operable for raising and loweringsaid blind.

6. In window construction, in combination, means forming a continuouslyperipheral frame, a pair of panes hermetically sealed in said frame inspaced relation to one another to form a space therebetween, a blindreciprocably disposed between said panes within said space and adaptedwhen lowered to cut off thermal radiation through said panes, lazy tongmeans connected to said blind and operable for raising and lowering saidblind, and endless cable means connected to said lazy tong means toeiect operation thereof.

'7. In window construction, in combination, means forming a continuouslyperipheral frame, a pair of panes hermetically sealed in said frame inspaced relation to one another to form a space therebetween. a blindreciprocably disposed between said panes within said space and adaptedwhen lowered to cut oi thermal radiation through said panes, meanswholly disposed within said space and operable for reciprocating saidblind, and power means disposed exteriorly of said frame buthermetically connected to said space for operating said means.

8. In window construction, in combination, means forming a continuouslyperipheral frame, a pair of panes hermetically sealed in said frame inspaced relation to one another to form a space therebetween, a blindreciprocably disposed between said panes within said space and adaptedwhen lowered to cut off thermal radiation through said panes, meanswholly disposed within said space and operable for reciprocating saidblind, and power means disposed wholly within said space for operatingsaid means.

9. In window construction, in combination, means forming a continuouslyperipheral frame, a pair of panes hermetically sealed in said frame inspaced relation to one another to form a space therebetween, a blindreciprocably disposed between said panes within said space and adaptedwhen lowered to cut off thermal radiation through said panes, and a lazytong at each Vertical side of said frame within said space connected tosaid blind and eiective upon actuation for opening and closing saidblinds.

10. In window construction, in combination, means forming a frame, apair of panes, means for mounting said panes in said frame in sealedspaced relationship whereby an air-tight space is formed between saidpanes, a blind, means mounting said blind for extensible movementbetween open and closed positions within said space, blind operatingmechanism disposed within said space and connected to said blind, saidmechanism being actuatable to effect movement of the blind, and meansfor actuating said operating mechanism.

11. In window construction, in combination, means forming a continuouslyperipheral frame, a pair of panes hermetically sealed in said frame inspaced relation to one another to form a space therebetween, a blind,means mounting said blind for extensible movement between open andclosed positions within said space, said blind being adapted when closedto cut off thermal radiation through said panes, and means including anactuatable device wholly disposed within said space for eiectingmovement of said blind between its open and closed positions.

12. A window construction comprising a plurality of spaced sheets ofglass disposed in a sash frame and being sealed about their edges toprovide a chamber sealed to exclude atmospheric dust, spaced parallellouver bars disposed in the chamber and being provided upon one sidewith highly reflective surfaces, said louver bars being rotatable abouttheir longitudinal axis to control the radiation passing through theconstruction and means operable while the chamber is completely sealedto change the positions of the louver bars about their axis.

13. A window construction comprising a plutix rality of spaced sheets ofglass disposed in a sash y frame and being sealed about their edges toprovide a chamber sealed against atmospheric dust, spaced parallellouver bars disposed in the chamber and being provided upon one sidewith highly reflective surfaces, said louver bars being rotatable abouttheir longitudinal axis to control the radiation passing through theconstruction and means operable while the chamber is completely sealedto change the positions of the louver bars about their axis, said meanscomprising an electrical motor sealed within the chamber and havingoperative driving connections with the louvers and being connected byconductors passing into the sealed chamber to means for supplyingelectrical current to the motor, said conductors also being in serieswith switch means for controlling the supply of current to the motor.

14. In window construction, in combination, means forming a frame, apair of panes mounted in said frame in spaced relation to one another toform a space therebetween, a blind reciprocably disposed between saidpanes within said space and adapted when lowered to cut off thermalradiation through said panes while admitting a certain amount of lighttherethrough, said blind comprising a plurality of parallel slatsadapted to nest together when the blind is raised and adapted to lie inuniformly spaced relationship in any position of the blind, a lazy tongat each vertical side of said frame within said space and connected tosaid blind and effective upon actuation for raising and lowering saidblind, an endless cable operatively mounted within said space, means forconnecting each ofsaid lazy tongs to said endless cable, and operatingmeans connected to said cable and adapted upon actuation to raise andlower said blind.

15. In window construction, in combination, means forming a continuouslyperipheral frame, a pair of panes hermetically sealed in said frame inspaced relation to one another to form a space therebetween, a blindreciprocably disposed between said panes within said space and adaptedwhen lowered to cut on" thermal radiation through said panes, aplurality of pulleys mounted on said frame within said space, an endlesscable trained over said pulleys and connected to said blind, andelectrically energizable driving means associated with said frame andconnected to said cable to operate said blind.v

16. In window construction, in combination, means forming a continuouslyperipheral frame, a pair of panes hermetically sealed in said frame inspaced relation to one another to form a space therebetween, a blindreciprocablyv disposed between said panes within said space and adaptedwhen closed to cut off thermal radiation through said panes, a pluralityof pulleys rotatably mounted on said frame within said space, an endlesscable trained over said pulleys, means forming a driving connectionbetween said cable and said blind whereupon reciprocation of said cablemoves said blind between its open and closed positions, and means foroperating said cable.

17. In window construction, in combination, means forming a continuouslyperipheral frame, a pair of panes hermetically sealed in said frame inspaced relation to one another to form a space therebetween, a blindreciprocably disposed between said panes within said space and adaptedwhen close to cut off thermal radiation through said panes, a pluralityof pulleys rotatably mounted on said frame within said space, an endlesscable trained over said pulleys, means forming a driving connectionbetween said cable and said blind whereupon reciprocation of said cablemoves said blind between its open and closed positions, an electricmotor secured to the outside of said frame, and means forming a drivingconnection between said motor and said cable for operating said cable.

18. In window construction, inA combination, means forming acontinuously peripheral frame, a pair of panes hermetically sealed insaid frame in spaced relation to one another to form a spacetherebetween, a blind reciprocably disposed between said panes withinsaid space and adapted when closed to cut oif thermal radiation throughsaid panes, a plurality of pulleys rotatably mounted on said framewithin'said space, an endless cable trained over said pulleys, meansforming a driving connection between said cable and said blind whereuponreciprocation of said cable moves said blind between its open and closedpositions, an electric motor secured to said frame within said space,and means forming a driving connection between said motor and saidcable.

ALFRED HENRY CHILTON.

